<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <title>Document</title>
  <style>
    * {
      box-sizing: border-box;
    }

    *:before, *:after {
      box-sizing: inherit;
    }

    body {
      width: 100%;
      height: 100%;
      overflow-x: hidden;
      font-size: 100%;
      line-height: 1.5;
    }

    .example {
      width: 100%;
      height: 100vh;
      max-width: 1200px;
      margin: 0 auto;
      display: flex;
      flex-direction: column;
    }

    header, footer {
      width: 100%;
      padding: 1em;
      text-align: center;
      font-size: 2rem;
      background-color: coral;
    }

    header {
      background-color: red;
    }

    .main {
      display: flex;
      height: 100%;
      font-size: 2rem;
    }

    nav, aside {
      padding: 1em;
    }

    nav {
      background-color: lightblue;
    }

    aside {
      background-color: lightgreen;
    }

    .content {
      background-color: orange;
      padding: 1em;
    }

    footer {
      order: -1;
    }

  </style>
</head>
<body>
  <div class="example">
    <header>
      header content here
    </header>
    <main class="main">
      <nav>
        nav content here
      </nav>
      <div class="content">
        main content here
      </div>
      <aside>
        aside content here
      </aside>
    </main>
    <footer>
      footer content here
    </footer>
  </div>
</body>
</html>